Ball on a String, 1D50.10

Topic and Concept:

• Motion in Two Dimensions, [:MotionIn2D#CentralForces: 1D50. Central Forces]

Location:

• Cabinet: [:MechanicsCabinet:Mechanic (ME)]

• Bay: [:MechanicsCabinetBayA2:(A2)]

• Shelf: #1

attachment:Ball02-400.jpg

Abstract:

A ball tied to a sting is whirled around in a vertical circle by hand.

Important Setup Notes:

• If using the brass ball, be carefull not to smack it on anything as the ball is hollow and dents easily.

Setup and Procedure:

1. Hold the string in hand securely.
2. Swing the ball into a circular, vertical trajectory.

Cautions, Warnings, or Safety Concerns:

• N/A

Discussion:

When the ball is swung it is given a momentum. The ball is unable to travel in a straight line, however. The string puts a tension on the ball causing it to arc upward. In other words, the ball is put into a circular trajectory with the centripetal force being provided by the tension in the string which is proportional to the tangential speed of the ball.

Videos:

• [https://www.youtube.com/user/LectureDemostrations/videos?view=1 Lecture Demonstration's Youtube Channel]

References:

• [https://en.wikipedia.org/wiki/Central_force Central Forces - Wikipedia]

• [https://en.wikipedia.org/wiki/Centripetal_force Centripetal Force - Wikipedia]

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